Arresting device, and snap member removal force measuring apparatus

ABSTRACT

A constraining device comprises a plurality of jaws  34  adapted to constrain the sides of an object of constraint, support shafts  35  rotatably supporting the respective jaws so as to allow the jaws to spread and become closed, first biasing means  36  adapted to bias the respective jaws to become closed, a jaw opening/closing drive member  62  arranged at the center of the jaws so as to move close to and away from the object of constraint and press the base end portions of the jaws to drive the jaws when moved in a first direction, a second biasing means  63  adapted to bias the jaw opening/closing drive member in the first direction in order to close the jaws and a temporary holding section  66  arranged at the jaw opening/closing drive member and adapted to be engaged with the base end portions of the jaws to block the jaw opening/closing drive member against moving in the first direction but allow the jaw opening/closing drive member to move in the first direction when force exceeding a predetermined level is applied to the jaw opening/closing drive member in the first direction.

TECHNICAL FIELD

This invention relates to a constraining device and also to a measuringinstrument for detaching force of snap member. More specifically, thepresent invention relates to a constraining device for constraining amember of constraint from around and a measuring instrument fordetaching force of snap member for measuring the necessary force fordetaching a snap member attached to a piece of fabric by means of theconstraining device.

BACKGROUND ART

Snap fasteners are used on garments to a large extent. A snap fastenerhas a structure in which a female snap member that is also referred toas socket member and a male snap member that is also referred to as stud(which are collectively referred to as snap members) are resilientlyengaged with and disengaged from each other. The snap members areattached to the oppositely disposed sides of respective pieces of fabricso as to face each other.

For examples, as shown in FIG. 12, a female snap member 1 and a malesnap member 2 are attached to the oppositely disposed sides of pieces offabrics 5, 6 by means of respective attaching members 3, 4 that arereferred to as prong members from the other sides of the pieces offabric.

If a snap member that is attached to the fabric of garments is easilydetached, an infant can swallow the snap member and/or the attachingmember. Therefore, it must be guaranteed that the force for detaching asnap member exceeds a predetermined level. Thus, in sewing factories,the force required for detaching a snap member is tested so as to keepthe snap members produced from the factory are under control and makesure that force exceeding a predetermined level is required fordetaching each of them.

For this reason, sewing companies in many countries adopt the EuropeanStandard “BS EN71-1: Safety of Toy, Mechanical and Physical Properties”,which defines that the force that can detach a snap member needs to beequal to or greater than “90N 10 seconds”.

Known gauges for measuring the force required for detaching a snapmember typically have a structure as shown in FIGS. 9 through 11.

The gauge comprises a base 10, a stage 11 arranged on the top surface ofthe base 10 and adapted to receive thereon a snap member attached to apiece of fabric and placed on it, a means for pressing the fabric 21adapted to press the fabric around the snap placed on the stage 11, aconstraining means 31 for constraining the sides of the snap member, apulling means 41 for pulling the constraining means 31 constraining thesnap member away (substantially vertically upward) from the means forpressing the fabric 21 and a gauging means 51 for gauging the pullingforce of the pulling means 41.

The stage 11 includes a support table 12 rigidly secured to the topsurface of the base 10, a support block 14 rigidly secured to thesupport table 12 by way of a support bolt 13 and a die 16 supported bythe support block 14 by way of a resilient spring section 15 formed bylaying a plurality of leaf springs, every other of which is laid upsidedown. A snap member attached to a piece of fabric is placed on the topsurface of the die 16.

The means for pressing the fabric 21 includes a support member 22standing upright from the support block 14, a fabric presser arm 24supported at a middle section thereof by the support member 22 at thetop end of the latter by way of a support shaft 23 so as to be able toswing around the shaft and press the fabric at an annular front end partthereof, a screw shaft 25 horizontally screwed into a middle section ofthe support member 22, a fabric presser arm regulating dial 26 engagedwith the screw shaft 25, a link holder 28 rotatably supported by thefabric presser arm regulating dial 26 by way of a bearing 27 and a link29 linking the link holder 28 and the rear end of the fabric presser arm24.

The constraining means 31 includes a threaded bolt 32 linked to a chain52 extending downward from the gauging means 51 by way of a joint 53, ajaw support plate 33 arranged at the lower end of the threaded bolt 32,three jaws 34 arranged to surround the snap member and having at thefront ends thereof respective engaging portions 34A adapted to beengaged with the sides of the snap member, support shafts 35 rotatablyholding middle portions of the jaws 34 to the jaw support plate 33 so asto allow the front end engaging portions 34A of the jaws 34 to spreadand become closed, turning/biasing means 36 for turning/biasing therespective jaws 34 around the corresponding respective support shafts 35so as to operate as fulcrums and open the front end engaging portions34A of the jaws 34 and a cam section 37 arranged so as to abut the baseend portions of the jaws 34 and turn the jaws 34 around the respectivesupport shafts 35 in order to close the front end engaging portions 34Aof the jaws 34 when it is engaged with the threaded bolts 32 and drivento move downward. The turning/biasing means 36 comprise respective coilsprings arranged respectively at the outsides of the corresponding jaws34. A jaw regulating dial 37A is arranged on the cam portion 37 as anintegral part of the latter.

The pulling means 41 includes an upright frame 42 standing on the topsurface of the base 10, a support frame 43 rigidly secured to an upperpart of the upright frame 42, a gauge support plate 45 vertically andslidably fitted to the support frame 43 by way of a sliding member 44and having the gauging means 51 fitted to the front side thereof and apulling up mechanism 46 for pulling up the gauge support plate 45. Thepulling up mechanism 46 comprises a top plate 47 arranged rectangularlyto the top end of the gauge support plate 45, a threaded bolt 48 screwedvertically into the support frame 43 to hold the top plate 47 and awheel 49 rigidly secured to the top end of the threaded bolt 48.

The gauging means 51 comprises a commercially available tensile forcemeasuring gauge 51A.

The necessary force for detaching a snap member is measured by means ofthe above described configuration in a manner as described below.

When the snap member attached to a piece of fabric is placed on the topsurface of the die 16, the jaw regulating dial 37A is rotated so as topinch and constrain the snap member at the sides thereof by means of thethree jaws 34.

At the same time, the fabric presser arm regulating dial 26 is rotatedso as to press the fabric by means of the annular front end part of thefabric presser arm 24. Then, the wheel 49 is rotated to pull up the snapmember that is constrained by the jaws 34 slowly by means of the tensileforce measuring gauge 51A and obtain the reading of the tensile forcemeasuring gauge 51A. If the snap member is not detached from the fabricbeyond a predetermined level of pulling force, it is guaranteed that thesnap member withstands a predetermined level of force trying to detachit from the fabric. When the snap member is pulled until it is detachedfrom the fabric, the necessary force for detaching it from the fabric isobserved.

Generally, when measuring the force required for detaching a snapmember, it is necessary to constrain the snap member by force not lessthan 200N because the force required for detaching a snap member isnormally about 200N.

With conventional measuring instrument for detaching force of snapmembers, the operator operates the jaw regulating dial 37A by rotatingit to constrain or release the snap member. Such a practice isaccompanied by the following problems.

(1) When measuring the snap member detaching force, the jaw regulatingdial 37A can be tightened excessively in fear of accidental release ofthe snap member from the jaws 34. Then, a large force is required toloosen the jaw regulating dial 37A that has been tightened excessivelyafter measuring the snap member detaching force. However, since theoperator manually rotates the jaw regulating dial 37A, the force appliedto it cannot be very large. For this reason, the operation of measuringthe snap member detaching force is a burden to the operator.

(2) As the snap member is constrained by excessive force, the front endsof the jaws 34 can be driven between the snap member and the fabric toseparate the snap member from the fabric and the snap member can bedeformed. There can be occasions where the snap member detaching forceis not correctly measured due to such phenomena.

Additionally, with conventional measuring instrument for detaching forceof snap members, the operator operates the fabric presser arm regulatingdial 26 by rotating it to press or release the fabric. Such a practiceis accompanied by the following problems.

(3) When measuring the snap member detaching force, the fabric presserarm regulating dial 26 can be tightened excessively in fear ofaccidental detachment of the fabric from the fabric presser arm 24.Then, a large force is required to loosen the fabric presser armregulating dial 26 that has been tightened excessively after measuringthe snap member detaching force. However, since the length of the fabricpresser arm 24 from the fulcrum to the link side end is shorter than thelength thereof from the fulcrum to the die side end, a large force isrequired for the operator to operate the fabric presser arm regulatingdial 26 to rotate it.

(4) The fabric presser arm 24 is made longer between the fulcrum and thedie side end thereof than between the fulcrum and the end thereoflocated close to the fabric presser arm regulating dial 26 so that thefabric presser arm 24 can be rotated by a necessary angle by rotatingthe fabric presser arm regulating dial 26 only to a small extent in viewof the fact that it is necessary to secure a gap of about 10 mm betweenthe fabric presser arm 24 and the die 16 when the snap member that isattached to the fabric is placed on the die 16. Therefore, the operatoris required to exert a large force when rotating the fabric presser armregulating dial 26. For this reason, the operation of measuring the snapmember detaching force is a burden to the operator.

Thus, the first object of the present invention is to provide aconstraining device that can reliably constrain a member of constraintwithout putting a burden on the operator.

The second object of the present invention is to provide a measuringinstrument for detaching force of snap member that can lessen the loadof the operator and accurately measure the necessary force for detachinga snap member.

DISCLOSURE OF THE INVENTION

According to the invention, there is provided a constraining device forconstraining an object of constraint, characterized by comprising: asupport member; a plurality of jaws adapted to be arranged around saidobject of constraint and having at the front ends thereof respectiveengaging portions to be engaged with the sides of the object ofconstraint; support shafts rotatably supporting the respective jaws atmiddle portions of the latter so as to allow the front end engagingportions of the jaws to spread and become closed; first biasing meansfor biasing the respective jaws to rotate around the respective supportshafts operating as fulcrums so as to bring the front end engagingportions of said jaws into an open state; a jaw opening/closing drivemember arranged internally relative to said plurality of jaws andadapted to move so as to make the jaws contact or release said object ofconstraint and rotate the jaws so as to press the base end portions ofthe jaws and close the front end engaging portions of the latter whenmoved in a direction of causing the jaws to contact the object ofconstraint or in a direction of causing the jaws to release the objectof constraint; and a second biasing means for biasing said jawopening/closing drive member in a first direction so as to bring thefront end engaging portions of the plurality of jaws into a closedstate.

With the above described configuration, the jaw opening/closing drivemember and the jaws are temporarily held so that the jaw opening/closingdrive member is blocked against moving in the first direction relativeto the jaws. While one or more than one temporary holding sections maybe used to temporarily block the movement of the jaw opening/closingdrive member, the frictional force generated on the sliding surfaces ofthe jaws and the jaw opening/closing drive member may alternatively beused.

When force exceeding a predetermined level is applied to the jawopening/closing drive member in this state, the temporarily blockedstate is released so that the jaw opening/closing drive member is biasedto move in the first direction by the biasing force of the secondbiasing means. Then, the jaw opening/closing drive member presses thebase end portions of the jaws to rotate the plurality of jaws so as toclose the front end engaging portions of the latter around therespective support shafts that operate as fulcrums. As a result, thefront end engaging portions of the jaws are closed to constrain theobject of constraint at its sides.

To release the object of constraint from the jaws, the jawopening/closing drive member is driven to move in the oppositedirection, or the second direction. At this time, since the biasingforce of the second biasing means that presses the jaw opening/closingdrive member in the first direction is reduced, only a small force isrequired to drive the jaw opening/closing drive member in the oppositedirection. Thereafter, since the force driving the jaw opening/closingdrive member gathers momentum, the jaw opening/closing drive memberpasses by the above described temporarily blocked position with thelittle force and returns to the state before constraining the object ofconstraint.

Therefore, the operator is only required to apply force that exceeds apredetermined level to the jaw opening/closing drive member in the firstdirection when constraining the object of constraint and only a smallforce to the jaw opening/closing drive member when releasing the objectof constraint. Thus, the operator can reliably constrain and release theobject of constraint without bearing any burden.

In a constraining device according to the invention, preferably eitherthe jaw opening/closing drive member is provided with a temporaryholding section adapted to be engaged with the base end portions of thejaws or the jaws are provided with respective temporary holding sectionsadapted to be engaged with the front end section of the jawopening/closing drive member so as to block the movement of the jawopening/closing drive member in the first direction caused by the secondbiasing means but become disengaged to allow the movement of the jawopening/closing drive member in the first direction when force exceedinga predetermined level is applied to the jaw opening/closing drive memberin the first direction.

With such a configuration, the jaw opening/closing drive member and thejaws are reliably held to a predetermined position by the temporaryholding section.

More specifically, the temporary holding section and the base endportions of the jaws are disengaged from each other when force exceedingthe predetermined level is applied to the jaw opening/closing drivemember in the first direction in a state where the jaw opening/closingdrive member is blocked against moving in the first direction by thetemporary holding section so that consequently the jaw opening/closingdrive member is driven to move in the first direction by the biasingforce of the second biasing means. Then, the jaw opening/closing drivemember presses the base end portions of the jaws to turn the jaws aroundthe respective support shafts that operate as fulcrums in the directionfor closing the front end engaging portions of the jaws. As a result,the front end engaging portions of the jaws constrains the sides of theobject of constraint as they are closed.

When the object of constraint is released from the jaws, the forcedriving the jaw opening/closing drive member gathers momentum andtherefore the temporary holding section can pass over the base endportions of the jaws with little force. After the temporary holdingsection passes over the base end portions of the jaws, the operatorreleases the jaw opening/closing drive member and then the temporaryholding section of the jaw opening/closing drive member is held by thebase end portions of the jaws to return to the state before constrainingthe object of constraint.

Thus, the temporary holding section reliably and temporarily holds thejaw opening/closing drive member and the state before constraining theobject of constraint can be defined at a predetermined position.

The temporary holding section of a constraining device according to theinvention may have any configuration so long as it can temporarily blockthe movement of the jaw opening/closing drive member in the firstdirection caused by the second biasing means and release the jawopening/closing drive member when a light force is applied thereto. Forexample, it may be a stepped holding section that is formed at the sideof the jaw opening/closing drive member facing the first direction andadapted to be engaged with the base end portions of the jaws.

Preferably, the jaw opening/closing drive member has a tapered sectionwhose diameter is increased along the direction opposite to the firstdirection from the temporary holding section. With a jaw opening/closingdrive member having such a tapered section can be prepared very easilyso as to be smoothly driven in the first direction by the second biasingmeans.

The angle of the tapered section is preferably between 10 and 80degrees. When the angle of the tapered section is between 10 and 80degrees, the component of force that is applied to the tapered sectionby the base end portions of the jaws and directed in the seconddirection (opposite to the first direction) is small and hence theobject of constraint can hardly be released from the jaws.

In a constraining device according to the invention, preferably themember holding the base end side of the second biasing means and the jawopening/closing drive member are provided with respective flanges thatcan be operated by one hand in a direction approaching the object ofconstraint to compress the second biasing means.

With this configuration, the operation of releasing the object ofconstraint from the jaws can be conducted by one hand to effectivelyimprove the efficiency of operation.

According to the invention, there is provided a measuring instrument fordetaching force of snap member, characterized by comprising: a means forpressing the fabric for pressing a piece of fabric attaching a snapmember around the snap member; a constraining means for constraining thesides of the snap member; a pulling means for pulling at least eitherthe constraining means or the means for pressing the fabric in thedirection separating the constraining means constraining the snap memberand the means for pressing the fabric; and a gauging means for gaugingthe pulling force of the pulling means; the constraining means having: asupport member; a plurality of jaws adapted to be arranged around thesnap member and having at the front ends thereof respective engagingportions to be engaged with the sides of the snap member; support shaftsrotatably supporting the respective jaws at middle portions of thelatter so as to allow the front end engaging portions of the jaws tospread and become closed; first biasing means for biasing the respectivejaws to rotate around the respective support shafts operating asfulcrums so as to bring the front end engaging portions of the jaws intoan open state; a jaw opening/closing drive member arranged internallyrelative to the plurality of jaws and adapted to move so as to make thejaws contact or release the object of constraint and rotate the jaws soas to press the base end portions of the jaws and close the front endengaging portions of the latter when moved in a direction of causing thejaws to contact the object of constraint or in a direction of causingthe jaws to release the object of constraint; and a second biasing meansfor biasing the jaw opening/closing drive member in a first direction soas to bring the front end engaging portions of the plurality of jawsinto a closed state.

When the force required for detaching a snap member from the fabricattaching the snap member by means of the above described configuration,firstly the fabric is held around the snap member by the means forpressing the fabric and the peripheral side of the snap member isconstrained by the constraining means. Then, the jaw opening/closingdrive member and the jaws are held temporarily to leave the jawopening/closing drive member in a state where it is blocked againstmoving in the first direction.

In this state, the jaw opening/closing drive member that is temporarilyheld is released when force exceeding the predetermined level is appliedto the jaw opening/closing drive member in the first direction so thatconsequently the jaw opening/closing drive member is driven to move inthe first direction by the biasing force of the second biasing means.Then, the jaw opening/closing drive member presses the base end portionsof the jaws to turn the jaws around the respective support shafts thatoperate as fulcrums in the direction for closing the front end engagingportions of the jaws. As a result, the front end engaging portions ofthe jaws constrain the sides of the snap member so that the snap memberis constrained. Therefore, the operator is only required to apply forcethat exceeds a predetermined level to the jaw opening/closing drivemember in the first direction when constraining the snap member. Thus,the operator can reliably constrain the snap member without bearing anyburden.

Subsequently, at least either the constraining means constraining thesnap member or the means for pressing the fabric is pulled by thepulling means in the direction of separating them. Then, the pullingforce of the pulling means is gauged by the gauging means.

When releasing the snap member held by the jaws after the operation ofgauging the necessary force for detaching the snap member, the jawopening/closing drive member is driven to move in the second direction.Since the biasing force of the second biasing means that presses the jawopening/closing drive member in the first direction is weakened at thistime, only a small force is required for driving the jaw opening/closingdrive member in the second direction. Thereafter, since the forcedriving the jaw opening/closing drive member gather momentum, it passesover the above described temporary holding position to return to thestate before constraining the snap member.

Thus, the load of the operator is reduced and, since the snap member isnot constrained by unnecessarily excessive force, the necessary forcefor detaching the snap member is measured accurately.

In a measuring instrument for detaching force of snap member accordingto the invention, preferably either the jaw opening/closing drive memberis provided with a temporary holding section adapted to be engaged withthe base end portions of the jaws or the jaws are provided withrespective temporary holding sections adapted to be engaged with thefront end section of the jaw opening/closing drive member so as to blockthe movement of the jaw opening/closing drive member in the firstdirection caused by the second biasing means but become disengaged toallow the movement of the jaw opening/closing drive member in the firstdirection when force exceeding a predetermined level is applied to thejaw opening/closing drive member in the first direction.

With such a configuration, the jaw opening/closing drive member and thejaws are reliably held to a predetermined position by the temporaryholding section.

More specifically, the temporary holding section and the base endportions of the jaws are disengaged from each other when force exceedingthe predetermined level is applied to the jaw opening/closing drivemember in the first direction in a state where the jaw opening/closingdrive member is blocked against moving in the first direction by thetemporary holding section so that consequently the jaw opening/closingdrive member is driven to move in the first direction by the biasingforce of the second biasing means. Then, the jaw opening/closing drivemember presses the base end portions of the jaws to turn the jaws aroundthe respective support shafts that operate as fulcrums in the directionfor closing the front end engaging portions of the jaws. As a result,the front end engaging portions of the jaws constrains the sides of theobject of constraint as they are closed.

When the object of constraint is released from the jaws, the forcedriving the jaw opening/closing drive member gathers momentum andtherefore the temporary holding section can pass over the base endportions of the jaws with little force. After the temporary holdingsection passes over the base end portions of the jaws, the operatorreleases the jaw opening/closing drive member and then the temporaryholding section of the jaw opening/closing drive member is held by thebase end portions of the jaws to return to the state before constrainingthe object of constraint.

Thus, the temporary holding section reliably and temporarily holds thejaw opening/closing drive member and the state before constraining theobject of constraint can be defined at a predetermined position.

The temporary holding section of a measuring instrument for detachingforce of snap member according to the invention may have anyconfiguration so long as it can temporarily block the movement of thejaw opening/closing drive member in the first direction caused by thesecond biasing means and release the jaw opening/closing drive memberwhen a light force is applied thereto. For example, it may be a steppedholding section that is formed at the side of the jaw opening/closingdrive member facing the first direction and adapted to be engaged withthe base end portions of the jaws.

Preferably, the jaw opening/closing drive member has a tapered sectionwhose diameter is increased toward the direction opposite to the firstdirection from the temporary holding section. With a jaw opening/closingdrive member having such a tapered section can be prepared very easilyso as to be driven in the first direction by the second biasing means.

The angle of the tapered section is preferably between 10 and 80degrees. When the angle of the tapered section is between 10 and 80degrees, the component of force that is applied to the tapered sectionby the base end portions of the jaws and directed in the seconddirection (opposite to the first direction) is small and hence the snapmember is not released from the jaws when the snap member detachingforce is as large as 200N. Therefore, this configuration provides anadvantage that the gauging operation can be conducted safely.

In a measuring instrument for detaching force of snap member accordingto the invention, preferably the member holding the base end side of thesecond biasing means and the jaw opening/closing drive member areprovided with respective flanges that can be operated by one hand in adirection approaching the object of constraint to compress the secondbiasing means.

With this configuration, the operation of releasing the object ofconstraint from the jaws can be conducted by one hand to effectivelyimprove the efficiency of operation.

In a measuring instrument for detaching force of snap member accordingto the invention, the means for pressing the fabric preferably has afabric presser arm adapted to press the fabric at the front end thereof,a support shaft supporting the fabric presser arm at a middle section ofthe arm so as to allow the latter to swing, a rotary shaft held inparallel with the support shaft and having a lever and a cam arranged atthe rotary shaft so as to swing the base end of the fabric presser armaround the support shaft that operates as fulcrum according to theoperation of turning the lever.

In another aspect of the invention, there is provided a measuringinstrument for detaching force of snap member comprising: a means forpressing the fabric for pressing a piece of fabric attaching a snapmember around the snap member; a constraining means for constraining thesides of the snap member; a pulling means for pulling at least eitherthe constraining means or the means for pressing the fabric in thedirection separating the constraining means constraining the snap memberand the means for pressing the fabric; and a gauging means for gaugingthe pulling force of the pulling means; the means for pressing thefabric having: the fabric presser arm adapted to press the fabric at thefront end thereof; a support shaft supporting the fabric presser arm ata middle section of the arm so as to allow the latter to swing; a rotaryshaft held in parallel with the support shaft and having a lever; and acam arranged at the rotary shaft so as to swing the base end of thefabric presser arm around the support shaft that operates as fulcrumaccording to the operation of turning the lever.

With the above described configuration, as the lever is operated toturn, the rotary shaft is rotated with the lever. Then, the cam arrangedat the rotary shaft causes the base end of the fabric presser arm toswing around the support shaft that operates as fulcrum. As a result,the front end of the fabric presser arm presses the fabric. Thus, thefabric is held by a light force to consequently lessen the load of theoperator.

In a measuring instrument for detaching force of snap member accordingto the invention, the cam of the means for pressing the fabricpreferably has a stopper section adapted to abut the base end of thefabric presser arm when the fabric presser arm is caused to swing in thedirection for pressing the fabric and the direction of force in whichthe base end of the fabric presser arm pushes the cam substantiallyagrees with the direction of the rotary shaft when the stopper sectionabuts the base end of the fabric presser arm.

With the above described configuration, none of the lever, the rotaryshaft and the cam return to the respective original positions if theoperator's hand releases the lever because the direction of force inwhich the base end of the fabric presser arm pushes the camsubstantially agrees with the direction of the rotary shaft when thestopper section of the cam abuts the base end of the fabric presser arm.Therefore, the fabric is reliably held by the front end of the fabricpresser arm.

Preferably, a measuring instrument for detaching force of snap memberaccording to the invention further comprises a die adapted to press thefabric between itself and the front end of the fabric presser arm and aresilient member supporting the die so as to allow the die to beresiliently displaced in the direction of pressing the fabric, the cambeing so profiled that it abuts the base end of the fabric presser armbefore the stopper section abuts the base end of the fabric presser armand the fabric presser arm slightly swings in the opposite directionwhen the stopper section abuts the base end of the fabric presser arm.

With the above described configuration, a measuring instrument fordetaching force of snap member according to the invention can be appliedto a variety of fabrics having different thicknesses by using aresilient member that supports the die. Additionally, as the cam firstlyabuts the base end of the fabric presser arm, the resilient membersupporting the die is compressed so that the fabric presser arm is madeto swing in the same direction. Thus, the fabric is pushed more tightly.As the cam rotates further, the resilient member supporting the die isextended so that the stopper section of the cam abuts the base end ofthe fabric presser arm. As a result, the force pushing the lever isreduced before the stopper section abuts the base end of the fabricpresser arm, the operator can feel that the fabric presser arm isbrought to the right position.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic front view of an embodiment of the invention,illustrating a principal part thereof;

FIG. 2 is a schematic lateral view of the embodiment of FIG. 1;

FIG. 3 is a schematic illustration of the embodiment of FIG. 1, showinga state thereof before constraining an object of constraint;

FIG. 4 is a schematic illustration of the embodiment of FIG. 1, showinga state thereof after constraining an object of constraint;

FIG. 5 is a schematic partially cut away view of the embodiment of FIG.1;

FIG. 6 is a schematic illustration of a modified means for rigidlyholding the spring abutting piece to the threaded bolt of the embodimentof FIG. 1;

FIG. 7 is a schematic illustration of another embodiment, showing astate thereof before constraining an object of constraint;

FIG. 8 is a schematic illustration of the embodiment of FIG. 7, showinga state thereof after constraining an object of constraint;

FIG. 9 is a schematic plan view of a known measuring instrument fordetaching force of snap member;

FIG. 10 is a schematic lateral view of the known measuring instrumentfor detaching force of snap member of FIG. 9;

FIG. 11 is a schematic illustration of the constraining means and themeans for pressing the fabric of the known measuring instrument fordetaching force of snap member of FIG. 10; and

FIG. 12 is a schematic cross sectional view of a snap member.

BEST MODE FOR CARRYING OUT THE INVENTION

Now, the present invention will be described by referring to theaccompanying drawings that illustrate an embodiment of the invention.

FIGS. 1 and 2 schematically illustrate a principal part of theembodiment of measuring instrument for detaching force of snap member.This embodiment of measuring instrument for detaching force of snapmember differs from conventional measuring instrument for detachingforce of snap members (such as a measuring instrument for detachingforce of snap member illustrated in FIGS. 9 through 11) in terms of theconstraining means and the means for pressing the fabric. Thisembodiment is same as or similar to known measuring instrument fordetaching force of snap members in terms of the remaining components. Inthe following description, the components that are same as or similar tothose illustrated in FIGS. 9 through 11 are denoted respectively by thesame reference symbols and will be described only briefly or will not bedescribed any further.

The constraining means 61 of this embodiment includes a threaded bolt 32linked to a chain 52 extending downward from the gauging means 51 by wayof a joint 53, a jaw support plate 33 arranged at the lower end of thethreaded bolt 32 so as to operate as support member, three jaws 34arranged to surround the snap member and having at the front endsthereof respective engaging portions 34A adapted to be engaged with thesides of the snap member, support shafts 35 rotatably holding middleportions of the jaws 34 to the jaw support plate 33 so as to allow thefront end engaging portions 34A of the jaws 34 to spread and becomeclosed, turning/biasing means 36 that are the first biasing means forturning/biasing the respective jaws 34 around the correspondingrespective support shafts 35 so as to operate as fulcrums and open thefront end engaging portions 34A of the jaws 34, a jaw opening/closingdrive members 62 arranged axially movably to surround the threaded bolt32 in such a way that, when it is moved in the first direction(downward), it presses the base end portions of the jaws 34 and turnsthe jaws 34 in a direction for closing the front end engaging portionsof the jaws 34 and an opening/closing biasing means 63 that is thesecond biasing means for biasing the jaw opening/closing drive member 62in the first direction of closing the front end engaging portions of thejaws 34.

The front end engaging portions 34A of the jaws 34 have a concaved innersurface, showing a claw-like profile, that snugly fits the sides of thesnap member.

As described above by referring to the prior art, the turning/biasingmeans 36 may be coil springs, although they may alternatively be annularelastic members such as O-rings or pieces of rubber.

As shown in FIGS. 3 and 4, the jaw opening/closing drive member 62 has atapered section 64 whose diameter is increased along the (upward)direction opposite to the first direction of movement of the jawopening/closing drive member 62 and a disk-shaped guard section 65formed integrally at the large diameter end of the tapered section 64.

The tapered section 64 has a tapered surface that shows an angle between10 and 80 degrees, which is about 60 degrees in this embodiment, and atemporary holding section 66 at the small diameter end thereof.

The temporary holding section 66 has a diameter smaller than the smalldiameter end of the tapered section 64 and the stepped section operatesas a stepped holding section having a curved surface that is engagedwith the inner curved surfaces of the base end portions of the jaws 34to block the movement of the jaw opening/closing drive member 62 in thefirst direction caused by the opening/closing biasing means 63. However,when force exceeding a predetermined level is exerted onto the jawopening/closing drive member 62 in the first direction, the temporaryholding section 66 is disengaged from the base end portions of the jaws34 to allow the jaw opening/closing drive member 62 to move in the firstdirection.

The guard section 65 has on the top surface thereof a recessed section67 for receiving the lower end of the opening/closing biasing means 63.

The opening/closing biasing means 63 comprises a coil spring 63A. Thecoil spring 63A has a lower end that is received in the recessed section67 and an upper end that abuts a spring abutting piece 68 screwed ontothe threaded bolt 32. As the spring abutting piece 68 is rotated anddisplaced in the axial direction of the threaded bolt 32, the downwardbiasing force of the coil spring 63A changes. While the threaded bolt 32is divided into two pieces with the spring abutting piece 68 interposedbetween them in FIGS. 4 and 5, it may alternatively be realized as onepiece.

As shown in FIG. 5, the means for pressing the fabric 71 of thisembodiment includes a fabric presser arm 72 that is substantiallyL-shaped and adapted to press the fabric relative to the die 16 at thefront end thereof, a support shaft 73 supporting the fabric presser arm72 to the support member 22 at a middle section of the arm 72 so as toallow the latter to swing, a bearing 74 arranged at the base end side ofthe fabric presser arm 72, a spring 75 that is arranged between thesupport member 22 and the fabric presser arm 72 and operates as biasingmeans for biasing the front end of the fabric presser arm 72 to moveaway from the top surface of the die 16, a rotary shaft 77 held inparallel with the support shaft 73 by the support member 22 and having alever 76 at an end thereof and a cam 78 arranged to the rotary shaft 77and adapted to cause the base end of the fabric presser arm 72 to swingaround the support shaft 73 that operates as fulcrum as the lever 76 isoperated to turn. Note that the die 16 is supported by a resilientspring section 15 that is a resilient member adapted to be resilientlydisplaced in the directions for pressing the fabric (upward and downwarddirections). The resilient spring section 15 is not limited to a leafspring as described above. It may alternatively be formed by using acoil spring, rubber or urethane.

As the lever 76 is turned from position (A) to position (B) in FIG. 2(counterclockwise in FIG. 2), the cam 78 does not contact the bearing 74until the lever is turned by a predetermined angle but eventually comesto contact the bearing 74. Then, the cam 78 produces a cam curve thatmakes the fabric presser arm 72 turn counterclockwise in FIG. 2. The cam78 is provided with a stopper section 78A that is engaged with thebearing 74 to block the lever 76 against turning further when the lever76 gets to position (B) in FIG. 2.

More specifically, the cam 78 is profiled in such a way that it abutsthe bearing 74 of the fabric presser arm 72 before the stopper section78A abuts the bearing 74 of the fabric presser arm 72 and the fabricpresser arm 72 is made to swing slightly in the opposite direction when(or immediately before) the stopper section 78A abuts the bearing 74 ofthe fabric presser arm 72, whereas the force with which the bearing 74of the fabric presser arm 72 pushes the cam 78 is substantially directedin the direction of the rotary shaft 77 when the stopper section 78Aabuts the bearing 74 of the fabric presser arm 72.

The lever 76 has a grip ball 76A at the front end thereof and thedistance between the rotary shaft 77 and the grip ball 76A is madesufficiently large.

Now, the operation of this embodiment of measuring instrument fordetaching force of snap member for gauging the necessary force fordetaching the snap member will be described below.

Firstly, a snap member attached to a piece of fabric is placed on thetop surface of the die 16 and, under this condition, the fabric ispressed against the top surface of the die 16 around the snap member bymeans of the means for pressing the fabric 71. To do this, the lever 76is turned from position (A) to position (B) in FIG. 2. Then, the fabricpresser arm 72 is turned counterclockwise in FIG. 2 by the cam 78 and,as a result, the fabric is pressed around the snap member by the frontend of the fabric presser arm 72.

At this time, the cam 78 abuts the bearing 74 of the fabric presser arm72 before the stopper section 78A abuts the bearing 74 of the fabricpresser arm 72 so that, when the stopper section 78A abuts the bearing74 of the fabric presser arm 72, the fabric presser arm 72 is made toshow a profile of a cam that is adapted to slightly swing in theopposite direction. Thus, as the cam 78 abuts the bearing 74 of thefabric presser arm 72 firstly, the resilient spring section 15supporting the die 16 is compressed to swing the fabric presser arm 72in the same direction. As the cam 78 is turned further, the resilientspring section 15 supporting the die 16 expands until the stoppersection 78A of the cam 78 abuts the bearing 74 of the fabric presser arm72. Therefore, the operator can feel that the fabric presser arm 72 isbrought to the right position because the necessary force for pressingthe lever 76 is reduced before the stopper section 78A abuts the bearing74.

When the fabric presser arm 72 is brought to the right position andhence the stopper section 78A of the cam 78 abuts the bearing 74 of thefabric presser arm 72, the force pressing the bearing 74 of the fabricpresser arm 72 is directed substantially in the direction of the rotaryshaft 77. Therefore, if the operator releases the lever 76 from thehand, none of the lever 76, the rotary shaft 77 and the cam 78 willreturn to the original position. Additionally, since the force pressingthe fabric is made to exceed 200N by the weight of the lever 76, that ofthe grip ball 76A and the length between the rotary shaft 77 and thegrip ball 76A, the fabric can be reliably pressed by the front end ofthe fabric presser arm 72.

Subsequently, the sides of the snap member is constrained by theconstraining means 61. At this time, force exceeding a predeterminedlevel is applied to the jaw opening/closing drive member 62 to press thelatter downward in a state where the jaw opening/closing drive member 62is blocked against moving downward by the temporary holding section 66.Then, the temporary holding section 66 and the inner curved surfaces ofthe base end portions of the jaws 34 are disengaged from each other andthe temporary holding section (stepped holding section) 66 is pusheddownward beyond the base end portions of the jaws 34 so thatconsequently the jaw opening/closing drive member 62 is moved downward.Then, as shown in FIG. 4, the tapered section 64 of the jawopening/closing drive member 62 presses the base end portions of thejaws 34 to turn the jaws 34 around the respective support shafts 35 thatoperate as fulcrums in the respective directions of closing the frontend engaging portions 34A of the jaws 34. As a result, the front endengaging portions 34A of the jaws 34 come to be engaged with the sidesof the snap member as they are closed so that the snap member isconstrained. In other words, the snap member is constrained whendownwardly directed force exceeding a predetermined level is applied tothe jaw opening/closing drive member 62 and hence the operator is notrequired to bear any burden for reliably constraining the snap member.

Thereafter, the snap member is pulled substantially rectangularlyrelative to the attaching surface by way of the pulling means 41. Then,the pulling force of the pulling means 41 is gauged by the gauging means51. Thus, the necessary force for detaching the snap member can beaccurately gauged with a reduced load on the part of the operator.

For the snap member to be released from the jaws 34, the front endengaging portions 34A of the jaws 34 need to be spread apart. Becausethe tapered section 64 of the jaw opening/closing drive member 62 thatabuts the base end portions of the jaws 34 shows an angle of about 30degrees, the upwardly directed component of force applied to the jawopening/closing drive member 62 by the base end portions of the jaws 34is small so that the snap member is not released from the jaws 34 if thesnap member detaching force is greater than 200N. Therefore, the gaugingoperation can be conducted safely.

On the other hand, the jaw opening/closing drive member 62 is pulledupward to release the snap member held by the jaws 34 after theoperation of gauging the snap member detaching force. At this time,since the coil spring 63A pressing the jaw opening/closing drive member62 downward is fully expanded, only a small force is required to pullthe jaw opening/closing drive member 62 upward. Thereafter, the forcepulling up the jaw opening/closing drive member 62 gathers momentum sothat the temporary holding section 66 can pass over the base endportions of the jaws 34 with little effort. After the temporary holdingsection 66 passes over the base end portions of the jaws 34, the jawopening/closing drive member 62 is released. Then, the temporary holdingsection 66 of the jaw opening/closing drive member 62 is held by thebase end portions of the jaws 34 to restore the state beforeconstraining the snap member.

Thus, with this embodiment, when a snap member is constrained by theconstraining means 61, the operator is only required to downwardly exertforce exceeding a predetermined level in order to release the jaws fromthe temporarily held state and constrain the snap member. On the otherhand, the snap member can be released by applying a light force to thejaw opening/closing drive member 62 in order to raise the latter andkeep the jaws in a temporarily held state. Thus, the snap member can bereliably constrained and released without putting a burden on theoperator.

Since the means for pressing the fabric 71 includes a fabric presser arm72 adapted to press a piece of fabric at the front end thereof, asupport shaft 73 supporting the fabric presser arm 72 at a middlesection of the arm 72 so as to allow the latter to swing, a rotary shaft77 held in parallel with the support shaft 73 and having a lever 76 anda cam 78 arranged to the rotary shaft 77 and adapted to cause the baseend of the fabric presser arm 72 to swing around the support shaft 73that operates as fulcrum as the lever 76 is operated to turn, the fabriccan be held with little effort without putting a burden on the part ofthe operator.

Additionally, when the stopper section 78A of the cam 78 abuts thebearing 74 of the fabric presser arm 72, the force pressing the bearing74 of the fabric presser arm 72 against the cam 78 is directedsubstantially in the direction of the rotary shaft 77. Therefore, if theoperator releases the lever 76 from the hand, none of the lever 76, therotary shaft 77 and the cam 78 will return to the original position.Still additionally, since the force pressing the fabric is made toexceed 200N by the weight of the lever 76, that of the grip ball 76A andthe length between the rotary shaft 77 and the grip ball 76A, the fabriccan be reliably pressed by the front end of the fabric presser arm 72.

Still additionally, the cam 78 abuts the bearing 74 of the fabricpresser arm 72 before the stopper section 78A abuts the bearing 74 ofthe fabric presser arm 72 so that, when the stopper section 78A abutsthe bearing 74 of the fabric presser arm 72, the fabric presser arm 72is made to show a profile of a cam that is adapted to slightly swing inthe opposite direction. Thus, as the cam 78 abuts the bearing 74 of thefabric presser arm 72 firstly, the resilient spring section 15supporting the die 16 is compressed to swing the fabric presser arm 72in the same direction. As the cam 78 is turned further, the resilientspring section 15 supporting the die 16 expands until the stoppersection 78A of the cam 78 abuts the bearing 74 of the fabric presser arm72. Therefore, the operator can feel that the fabric presser arm 72 isbrought to the right position because the necessary force for pressingthe lever 76 is reduced before the stopper section 78A abuts the bearing74.

Note that the embodiment can be applied to a variety of fabrics havingdifferent thicknesses because the die 16 is supported by the resilientspring section 15 in such a way that it can be resiliently displaced inthe direction of pressing the fabric.

Still additionally, the spring 75 is arranged as biasing means forbiasing the front end of the fabric presser arm 72 of the means forpressing the fabric 71 to move away from the top surface of the die 16,a gap is secured between the front end of the fabric presser arm 72 andthe top surface of the die 16 so that a piece of fabric can be insertedthrough the gap without difficulty.

Furthermore, in a state where the snap member is constrained by theconstraining means 61 and the fabric is pressed around the snap memberby the means for pressing the fabric 71, the snap member is pulledsubstantially rectangularly relative to the attaching surface by way ofthe pulling means 41. Then, the pulling force of the pulling means 41 isgauged by the gauging means 51. Thus, the necessary force for detachingthe snap member can be accurately gauged with a reduced load on the partof the operator.

The present invention is by no means limited to the above describedembodiment of measuring instrument for detaching force of snap member,which may be modified in a manner as described below.

While a single temporary holding section 66 is provided in the aboveembodiment, a number of temporary holding sections 66 may be arrangedalong the axial direction of the jaw opening/closing drive member 62.

In the above embodiment, the tapered section 64 of the jawopening/closing drive member 62 is made to have a diameter thatgradually increases in the opposite direction (upward) that is oppositeto the first direction (downward) of movement of the jaw opening/closingdrive member 62. Alternatively, it may be so arranged that the taperedsection 64 has a diameter that gradually decreases in the oppositedirection or the upward direction and the jaw opening/closing drivemember 62 is biased in the opposite direction (upward) by theopening/closing biasing means 63.

With such an configuration, as force exceeding a predetermined level isapplied in the second direction (upward) to the jaw opening/closingdrive member 62 in a state where the jaw opening/closing drive member 62is blocked against moving upward by the temporary holding section 66,the temporary holding section 66, the base end portions of the jaws 34are disengaged from each other so that the jaw opening/closing drivemember 62 is moved in the second direction (upward) by the biasing forceof the opening/closing biasing means 63. As a result, the jaws 34 areturned in respective directions of closing the front end engagingportions 34A of the jaws 34. Thus, this modified configuration providesadvantages similar to those of the above described embodiment.

Additionally, the temporary holding section 66 may have any differentconfiguration so long as it can temporarily block the jawopening/closing drive member 62 against moving in the first directionand the temporarily blocked state can be released with little effort.

For example, the surface of the (lower) end of the jaw opening/closingdrive member 62 as viewed in the first direction may be made to showundulations or coarse to provide a friction surface which isfrictionally engaged with the base end portions of the jaws 34 tooperate as friction-holding portion such a friction-holding section mayalternatively be formed by using an engaging O-ring that is typicallymade of rubber in place of a friction surface having undulations or acoarse friction surface.

FIGS. 7 and 8 illustrate another embodiment of the present invention.The components of this embodiment other than the jaw opening/closingdrive member 62, the jaws 34 and the spring abutting piece 68 are sameas those of the embodiment of FIGS. 1 through 6 and hence will not bedescribed any further.

The jaw opening/closing drive member 162 is provided with a taperedsection 64 and a guard section 65 as in the case of the above describedembodiment. However, no stepped temporary holding section 66 is formedat the front end side of the tapered section 64. Instead, a projectingtemporary holding section 166 is formed at the inside of each of thejaws 34.

Referring to FIG. 7, the temporary holding sections 166 formedrespectively at the insides of the corresponding jaws 34 are engagedwith the peripheral edge of the front end of the jaw opening/closingdrive member 162. With this configuration, while the jaw opening/closingdrive member 162 is biased in the first direction (downward) by theopening/closing biasing means 63, it is engaged with and temporarilyheld by the temporary holding sections 166. Under this condition, thebase end sides of the jaws 34 contact a relatively narrow area of thetapered section 64 so as to be apt to slide there and the front endengaging portions 34A are held in a state of being spread apart.

Referring to FIG. 8, as the jaw opening/closing drive member 162 that istemporarily held is pushed in the first direction (downward), thetemporary holding sections 166 are disengaged from the front end sectionof the jaw opening/closing drive member 162 so that the jawopening/closing drive member 162 moves in the first direction (downward)relative to the jaws 34 and the base ends of the jaws 34 slide along thetapered section 64 and spread apart relative to each other (thetemporary holding sections 166 of the jaws 34 slide along the taperedsection 64 from respective predetermined positions and spread apartrelative to each other in this embodiment) so that the jaws 34 areturned and their front end engaging portions 34A become closed.

Thus, this configuration provides advantages similar to those of theabove described embodiment.

Note that a guard section 68A is formed at the spring abutting piece 68in the embodiment of FIGS. 7 and 8. Therefore, this embodiment providesan additional advantage that the operation of bringing the springabutting piece 68 and the jaw opening/closing drive member 162 close toeach other against the opening/closing biasing means 63 can be performedeasily by the operator by grasping the guard section 65 of the jawopening/closing drive member 162 and the guard section 68A of the springabutting piece 68 by one hand.

The temporary holding section may be also modified in a manner asdescribed below.

If the frictional force generated at the sliding/contacting area of thejaw opening/closing drive member 62 and those of the jaws 34 issufficiently large for temporarily blocking the relative movement of thejaw opening/closing drive member 62 and the jaws 34, it is not necessaryto provide the constraining means 61 with a temporary holding section.Alternatively, the relative movement of the jaw opening/closing drivemember 62 and the jaws 34 can be blocked temporarily by using a clip orthe like. In short, the provision of such a temporary holding section isnot indispensable for the purpose of the invention.

If the constraining means 61 is not provided with a temporary holdingsection, an operation of constraining and releasing can be performed asin the case of the above described embodiments to provide advantagessimilar to those of the embodiments provided that the temporary holdingeffect is realized by friction or the like.

Additionally, if the constraining means 61 is not designed to perform atemporary holding operation unlike the above described embodiments, theobject of constraint can be released from a constrained state by pushingup the opening/closing biasing means 63 and brought back into aconstrained state by suspending the effort of pushing up theopening/closing biasing means 63. Therefore, from this point of view,the present invention provides a remarkable advantage of ease ofoperation if compared with conventional screw type gauges.

While the constraining means 61 is pulled in a direction of moving awayrelative to the means for pressing the fabric 71 in each of the abovedescribed embodiments, conversely the means for pressing the fabric 71may be pulled in a direction of moving away relative to the constrainingmeans 61. Alternatively, both the constraining means 61 and the meansfor pressing the fabric 71 may be pulled so as to be moved away relativeto each other.

While the threaded bolt 32 is divided into two parts and linked by thespring abutting piece 68 in each of the above described embodiments, thethreaded bolt 32 may be used without dividing it as shown in FIG. 6.Then, the threaded bolt 32 is made to pass through the spring abuttingpiece 68 in such a way that the latter can move relative to the formerand the spring abutting piece 68 can be rigidly held to a desiredposition on the threaded bolt 32 by means of a nut 69 that is screwedonto the threaded bolt 32.

Additionally, the present invention is not limited to measuringinstrument for detaching force of snap members as described above by wayof embodiments and can be applied to constraining devices that compriseonly a constraining means.

For example, in a situation where a bolt is screwed onto a member bymeans of a part assembling apparatus, a constraining device according tothe invention may be used as a component of the assembling apparatus insuch a way that the head of the bolt is constrained by the constrainingmeans 61, which is subsequently driven to rotate by a rotating/drivingmeans. A constraining device according to the invention may also be usedfor catching a wafer in a wafer transporting means.

INDUSTRIAL APPLICABILITY

The present invention can be applied to a constraining device forconstraining an object of constraint such as a snap member attached to apiece of fabric and also to a measuring instrument for detaching forceof snap member for gauging the necessary force for detaching the snapmember attached to a piece of fabric.

1. A constraining device for constraining an object of constraint,characterized by comprising: a support member; a plurality of jawsadapted to be arranged around said object of constraint and having atthe front ends thereof respective engaging portions to be engaged withthe sides of the object of constraint; support shafts rotatablysupporting the respective jaws at middle portions of the latter so as toallow the front end engaging portions of the jaws to spread and becomeclosed; first biasing means for biasing the respective jaws to rotatearound the respective support shafts operating as fulcrums so as tobring the front end engaging portions of said jaws into an open state; ajaw opening/closing drive member arranged internally relative to saidplurality of jaws and adapted to move so as to make the jaws contact orrelease said object of constraint and rotate the jaws so as to press thebase end portions of the jaws and close the front end engaging portionsof the jaws when moved in a direction of causing the jaws to contact theobject of constraint or in a direction of causing the jaws to releasethe object of constraint; and a second biasing means for biasing saidjaw opening/closing drive member in a first direction so as to bring thefront end engaging portions of said plurality of jaws into a closedstate.
 2. The constraining device according to claim 1, wherein eithersaid jaw opening/closing drive member is provided with a temporaryholding section adapted to be engaged with the base end portions of saidjaws or said jaws are provided with respective temporary holdingsections adapted to be engaged with the front end section of said jawopening/closing drive member so as to block the movement of said jawopening/closing drive member in the first direction caused by saidsecond biasing means but become disengaged to allow the movement of saidjaw opening/closing drive member in the first direction when forceexceeding a predetermined level is applied to the jaw opening/closingdrive member in the first direction.
 3. The constraining deviceaccording to claim 2, wherein the temporary holding section is realizedas a stepped holding section that is formed at the side of the jawopening/closing drive member facing the first direction and adapted tobe engaged with the base end portions of the jaws.
 4. The constrainingdevice according to claim 2 or 3, wherein the temporary holding sectionis formed at the side of the jaw opening/closing drive member facing thefirst direction and the jaw opening/closing drive member has a taperedsection whose diameter is increased along the direction opposite to thefirst direction from said temporary holding section.
 5. The constrainingdevice according to claim 4, wherein the angle of the tapered section isbetween 10 and 80 degrees.
 6. The constraining device according to anyof claims 1 through 5, wherein the member holding the base end side ofthe second biasing means and the jaw opening/closing drive member areprovided with respective flanges that can be operated by one hand in adirection approaching the object of constraint to compress the secondbiasing means.
 7. A measuring instrument for detaching force of snapmember, characterized by comprising: a means for pressing the fabric forpressing a fabric of garments attaching a snap member around the snapmember; a constraining means for constraining the sides of the snapmember; a pulling means for pulling at least either the constrainingmeans or the means for pressing the fabric in the direction separatingthe constraining means constraining the snap member and the means forpressing the fabric; and a gauging means for gauging the pulling forceof the pulling means; said constraining means having: a support member;a plurality of jaws adapted to be arranged around said snap member andhaving at the front ends thereof respective engaging portions to beengaged with the sides of the snap member; support shafts rotatablysupporting the respective jaws at middle portions of the latter so as toallow the front end engaging portions of the jaws to spread and becomeclosed; first biasing means for biasing the respective jaws to rotatearound the respective support shafts operating as fulcrums so as tobring the front end engaging portions of said jaws into an open state; ajaw opening/closing drive member arranged internally relative to saidplurality of jaws and adapted to move so as to make the jaws contact orrelease said object of constraint and rotate the jaws so as to press thebase end portions of the jaws and close the front end engaging portionsof the latter when moved in a direction of causing the jaws to contactthe object of constraint or in a direction of causing the jaws torelease the object of constraint; and a second biasing means for biasingsaid jaw opening/closing drive member in a first direction so as tobring the front end engaging portions of said plurality of jaws into aclosed state.
 8. The measuring instrument for detaching force of snapmember according to claim 7, wherein either said jaw opening/closingdrive member is provided with a temporary holding section adapted to beengaged with the base end portions of said jaws or said jaws areprovided with respective temporary holding sections adapted to beengaged with the front end section of said jaw opening/closing drivemember so as to block the movement of said jaw opening/closing drivemember in the first direction caused by said second biasing means butbecome disengaged to allow the movement of said jaw opening/closingdrive member in the first direction when force exceeding a predeterminedlevel is applied to the jaw opening/closing drive member in the firstdirection.
 9. The measuring instrument for detaching force of snapmember according to claim 8, wherein the temporary holding section isrealized as a stepped holding section that is formed at the side of thejaw opening/closing drive member facing the first direction and adaptedto be engaged with the base end portions of the jaws.
 10. The measuringinstrument for detaching force of snap member according to claim 8 or 9,wherein the temporary holding section is formed at the side of the jawopening/closing drive member facing the first direction and the jawopening/closing drive member has a tapered section whose diameter isincreased along the direction opposite to the first direction from saidtemporary holding section.
 11. The measuring instrument for detachingforce of snap member according to claim 10, wherein the angle of thetapered section is between 10 and 80 degrees.
 12. The measuringinstrument for detaching force of snap member according to any of claims7 through 11, wherein the member holding the base end side of the secondbiasing means and the jaw opening/closing drive member are provided withrespective flanges that can be operated by one hand in a directionapproaching the object of constraint to compress the second biasingmeans.
 13. The measuring instrument for detaching force of snap memberaccording to any of claims 7 through 12, wherein the means for pressingthe fabric has a fabric presser arm adapted to press the fabric at thefront end thereof, a support shaft supporting the fabric presser arm ata middle section of the arm so as to allow the latter to swing, a rotaryshaft held in parallel with the support shaft and having a lever and acam arranged at the rotary shaft so as to swing the base end of thefabric presser arm around the support shaft that operates as fulcrumaccording to the operation of turning the lever.
 14. The measuringinstrument for detaching force of snap member according to claim 13,wherein the cam has a stopper section adapted to abut the base end ofthe fabric presser arm when the fabric presser arm is caused to swing inthe direction for pressing the fabric and the direction of force inwhich the base end of the fabric presser arm pushes the camsubstantially agrees with the direction of the rotary shaft when thestopper section abuts the base end of the fabric presser arm.
 15. Themeasuring instrument for detaching force of snap member according toclaim 14, further comprising: a die adapted to press the fabric betweenitself and the front end of the fabric presser arm and a resilientmember supporting the die so as to allow the die to be resilientlydisplaced in the direction of pressing the fabric; the cam being soprofiled that it abuts the base end of the fabric presser arm before thestopper section abuts the base end of the fabric presser arm and thefabric presser arm slightly swings in the opposite direction when thestopper section abuts the base end of the fabric presser arm.
 16. Ameasuring instrument for detaching force of snap member comprising: ameans for pressing the fabric for pressing a fabric of garmentsattaching a snap member around the snap member; a constraining means forconstraining the sides of the snap member; a pulling means for pullingat least either the constraining means or the means for pressing thefabric in the direction separating the constraining means constrainingthe snap member and the means for pressing the fabric; and a gaugingmeans for gauging the pulling force of the pulling means; said means forpressing the fabric having: a fabric presser arm adapted to press thefabric at the front end thereof; a support shaft supporting the fabricpresser arm at a middle section of the arm so as to allow the latter toswing; a rotary shaft held in parallel with the support shaft and havinga lever; and a cam arranged at the rotary shaft so as to swing the baseend of the fabric presser arm around the support shaft that operates asfulcrum according to the operation of turning the lever.
 17. Themeasuring instrument for detaching force of snap member according toclaim 16, wherein the cam has a stopper section adapted to abut the baseend of the fabric presser arm when the fabric presser arm is caused toswing in the direction for pressing the fabric and the direction offorce in which the base end of the fabric presser arm pushes the camsubstantially agrees with the direction of the rotary shaft when thestopper section abuts the base end of the fabric presser arm.
 18. Themeasuring instrument for detaching force of snap member according toclaim 17, further comprising: a die adapted to press the fabric betweenitself and the front end of the fabric presser arm and a resilientmember supporting the die so as to allow the die to be resilientlydisplaced in the direction of pressing the fabric; the cam being soprofiled that it abuts the base end of the fabric presser arm before thestopper section abuts the base end of the fabric presser arm and thefabric presser arm slightly swings in the opposite direction when thestopper section abuts the base end of the fabric presser arm.